- a unit of electric charge noting the amount of electricity transferred by a current of one ampere in one hour, equal to 3600 coulombs. Abbreviations: Ah, a.h., amp-hr, amp. hr.
- a practical unit of quantity of electricity; the quantity that flows in one hour through a conductor carrying a current of 1 ampere. 1 ampere-hour is equivalent to 3600 coulombs
